Conventionally, single-box vehicles such as station wagons and vans include a third vehicle seat row in addition to the front and rear seat rows. A seat in such a third seat row is disclosed in, for example, Patent Documents 1 to 4. The legs for a seat cushion of the vehicle seat are detachably located on the vehicle floor.
When in use, the seat cushion is arranged at a horizontal use position, and a seat back is arranged upright on the seat cushion. When the vehicle seat is stored, the seat back is collapsed onto the seat cushion, and in a state in which the leg is detached from the vehicle floor, the seat cushion and the seat back are flipped up along the side wall of the vehicle floor to be arranged in a storage position.
In such a flip-up vehicle seat, mounting lugs extend from a cushion frame of the seat cushion, and the leg is attached to the mounting lugs via brackets. When mounting such a leg on the cushion frame, the leg is pivotably attached to the brackets in advance, and the brackets are tightened to the mounting lugs of the cushion frame.
However, when the vehicle seat is stored, the seat cushion is flipped up to be arranged along the side wall of the vehicle floor, and the leg is pivoted toward the seat cushion to be folded. In this state, the leg projects toward the interior of the vehicle from the cushion frame by the amount corresponding to the thickness of the leg.
Therefore, in a state in which the seat cushion is flipped up, the width of the luggage compartment of the vehicle undesirably becomes narrow. Also, if the projecting amount of the leg from the cushion frame is great, the appearance is undesirably deteriorated.    Patent Document 1: Japanese Laid-Open Patent Publication No. 8-142725    Patent Document 2: Japanese Laid-Open Patent Publication No. 10-109578    Patent Document 3: Japanese Laid-Open Patent Publication No. 11-147432    Patent Document 4: Japanese Laid-Open Patent Publication No. 2008-126742